1. Field of the Invention
The present invention relates generally to the field of subsurface ocean data telemetry and in particular to a system utilizing a standard surface buoy mooring line as the transmission medium.
2. Description of the Prior Art
At the present time most in situ deep ocean data collected over any length of time are stored on magnetic tape or other recording medium in a subsurface instrument, and are not available until the instrument is recovered. However, the current availability of inexpensive satellite telemetry has prompted interest in developing a technique to permit near real time telemetering of oceanographic data from the deep ocean to the laboratory.
Solar powered radio transceivers mounted on surface ocean buoys are presently in use. These transceivers send telemetry data to satellite receivers and are useful for collecting ocean surface and weather information. Systems capable of sending subsurface oceanographic data to satellites over relatively long periods of time, however, are not known to be available. One problem with subsurface instruments is finding reliable means for the transfer of data between the instruments and a surface transceiver.
It has been proposed that the inductive properties of the cable on which subsurface instruments are suspended be used to transmit collected oceanographic data. Such a system is disclosed in U.S. Pat. No. 3,314,009 to Murdock in which an electrically insulated cable with a conductive core is lowered into the ocean by a ship. Multiple instruments are clamped onto the cable, which inductively transfer data into the cable. A receiver on the ship connected to the cable receives and records the information.
What is needed is a system which addresses the needs of in situ subsurface data collection utilizing existing buoy mooring lines and radio transmitters and receivers and which permits reliable transfer of oceanographic data for extended periods without the requirement of frequent battery replacement.